Other Parts Discussed in Thread: TIDA-00748
Hello All,
My customer is designing a Synch Boost LED Driver using LM5122 to power ultraviolet LEDs for the curing of bodywork materials.
Customer is looking for support if possible for the compensation circuit.
The circuit is similar to the one you proposed in TI-design TIDA-00748. However, customer has a doubt about the compensation of the control loop.
In fact, in your TI-design I see that the 0dB frequency is around 10KHz while with customer scheme I get a 0dB frequency of about 600Hz (therefore a very limited band). Customer did the measurement with a GDF and an oscilloscope following the document AN-1889.
Would you have a document explaining how to calculate the compensation components for the LM5122 used as a LED driver? In fact, following the formulas shown in the datasheet I cannot find correspondence with the components of the TI-design indicated above. I imagine that the presence of current feedback will change some passages.
Unlike the TI-design mentioned above, customer circuit works in these conditions:
VIN: from 17V to 20V
VOUT: 35V
IOUT: 2.7A
FSW: 400kHz
Furthermore the sensing of the load current is low-side rather than high-side.
Do you have any comments/advice here?
Many Thanks,
Antonio
